The subject system and method are generally directed to the detection of a projectile and a measurement of its position. In particular, although not exclusively, a detection system measures the position, speed, and other trajectory features of a projectile such as a ball as it crosses discretely pulsed beams of light projected by the system. Although the system has particular applications in the games of baseball or softball, where it may be installed in a home plate and used to determine whether a ball has entered a predetermined strike zone, the system is also useful in other contexts where the measurement of a projectile position and/or speed within a predetermined three-dimensional space is desired.
In the games of baseball and softball, the strike zone is a conceptual right pentagonal prism over the home plate which defines the boundaries through which a pitch must pass in order to be counted as a “strike” when a batter does not swing the bat.
As shown in FIG. 1, the top 10 of the strike zone 12 is defined in the official rules of baseball as a horizontal line at the midpoint between the top of the batter's shoulders and the top of the uniform pants. The bottom 14 of the strike zone 12 is a line at the hollow beneath the kneecap of the batter. The right and left boundaries 16 and 18 of the strike zone 12 correspond to the edges 20 and 22 of the home plate 24. A pitch that touches the outer boundary of the strike zone is as much a strike as a pitch that is thrown right down the center of the strike zone. A pitch at which the batter does not swing and which does not pass through the strike zone is called a ball.
The home plate, formally designated home base in the rules, is a final base that the player must touch to score. The home plate is a five-sided slab of whitened rubber that is set at ground level. The batter stands in the batter's box when ready to receive a pitch from a pitcher.
In baseball, an umpire is a person charged with officiating the game, including beginning and ending the game, enforcing the rules of the game and the grounds, making judgment calls on plays, and handling disciplinary actions. In a game officiated by two or more umpires, the umpiring chief (home-plate umpire) is the umpire who is in charge of the entire game. This umpire calls balls and strikes, as well as fair balls and foul balls short of first/third base, and makes most calls concerning the batter or base runners near home plate. The umpire 26 is usually positioned behind the catcher's box and declares whether the pitch is a strike or a ball.
It is clear that human error may be present in judging whether a pitch passes through the strike zone or outside the boundaries. This is especially true in the case of little league and scholastic league baseball games where the umpires are typically non-professional and/or volunteers. The probability of human errors in these situations is increased.
It is therefore desirable to provide a mechanism which reduces human error in categorizing the pitch as a “ball” or a “strike” especially for use in baseball and/or softball leagues where the umpires are typically non-professional or volunteers.
It is additionally desirable for this mechanism to be efficient in processing and power consumption while also being accurate in its categorization.
It is additionally desirable for this mechanism to accurately and efficiently operate in a variety of fluctuating lighting conditions.